1. Field of the Invention
The subject invention relates to a method for operating and deploying a resource tracking system of the type used by emergency responders at the scene of a chaotic event such as a fire or the like.
2. Related Art
Certain situations, such as emergencies and emergency drills or exercises, create chaotic environments where it can be difficult to track and locate personnel and equipment. For example, if a building is evacuated, the security manager must know whether all of the workers inside the building have left and where they are presently located. For another example, an incident commander is placed in charge at a large fire with multiple fire departments responding. The incident commander must know at all times what personnel and equipment are on site. In yet another example, it may be necessary to track the exposure of people and objects to toxic contaminants.
Emergency events usually happen at unknown and unplanned locations. There is no opportunity to set up equipment ahead of time. Under chaotic conditions, quick response time and data collection accuracy are critical tools. The scene or incident commander is in need of a portable, rapidly deployable system which can help capture and provide tracking information for response personnel and equipment with little or no set up effort.
The prior art has proposed various systems for locating tagged personnel and equipment at the scene of an event. Generally, tags or other transmitting devices are carried by the personnel or affixed to the equipment and transmit a signal that is received by one or more readers erected about the perimeter of a scene. These tags or other transmitting devices are generally of two styles. In one style, the tag determines its own location usually based on a feed from a navigational satellite such as GPS. The tag then transmits its known location to the reader, which acts as a relay passing the tag location on to a scene commander equipped with a graphical user interface so that the position of all of the tags, and hence the associated resources, can be monitored. Tags of this first type are expensive devices and are useful only so long as their ability to self-determine location is properly functioning. If the tag moves into an area where its ability to communicate with the navigational satellite is interrupted, the functionality of the tracking system is compromised.
A second type of tag, much less expensive than the first type described above, transmits only an identification number and perhaps other basic information. The second type of tag does not have the capability, or does not rely on the ability, to self determine and transmit data corresponding to its location. Rather, these systems rely upon a calibrated array of strategically arranged readers which sense and triangulate the position of the tags, and then relay this calculated position back to the scene commander. While the use of these second type, low cost tags is generally preferred, this method of tracking personnel and equipment is disadvantageous because the readers must be carefully set up and calibrated prior to use. Such calibration may require skilled technical people placing the readers at precise locations about the scene of the chaotic event. Not only does this calibration step consume much valuable time, but also is not adaptable to the scene of a chaotic event because the scene can actually shift during its course. Take for example a fire, which migrates from one building to the next.
Another drawback of prior art systems arise out of the inaccurate calculation of tag locations. As can be imagined, obstructions present in the chaotic scene, such as heavy concrete walls, thick metallic features, and the like can affect the signal strength of wireless radio signals passing therethrough. Likewise, electromagnetic reflective surfaces can affect the vector of radio signals emitted by the wireless tags. These and other related factors can render false tag location calculations by the tracking system software. As a result, a scene commander relying upon the calculated position of sensed tags within the scene may draw inaccurate conclusions because the actual position of a sensed tag is not properly understood.
And yet another drawback found in prior art systems arises out of the general inability to determine whether a tag is actually being tracked by the system at any given moment. Because such tags can be damaged through use, and also because the sensing range is usually limited, there exists a need to determine whether a tag being used by an emergency responder, at any given moment, is currently recognized by the tracking system.